Sailor Lethe

セーラー・レテ

Sailor Lethe and Sailor Mnemosyne appear exclusively in Act 48 of the manga. They are twin sisters originating from the planets Lethe and Mnemosyne, respectively. Their home worlds were small, impoverished, and ravaged by violence and chaos. When Galaxia arrived, bringing death and ruin, the sisters had no choice but to follow her, hoping to eventually find peace.
Sailor Lethe’s name derives from a naiad in Greek mythology and from a river in the Greek underworld where dead souls go to forget their past lives before reincarnation.
Sailor Lethe initially introduces herself as the ferryman of the desert river. She traps Eternal Sailor Moon at the bottom of the River of Oblivion, kills Luna, Artemis, and Diana, and attacks Sailor Moon. She is halted by Sailor Mnemosyne, who states that Sailor Moon has suffered enough.
Lethe claims that Sailor Moon’s Sailor Crystal, the Ginzuishou, is the cause of all the wars they are enduring, and that destroying it will bring peace. Sailor Moon offers her life if it will end the violence. Lethe and Mnemosyne are so moved by her self-sacrifice that they realize the war will continue regardless of whether Sailor Moon dies. Just as they are about to release the Senshi, Sailor Chi and Sailor Phi appear. These two call Lethe and Mnemosyne useless fools and take their Sailor Crystals, which kills them.
Sailor Lethe possesses an attack called "Galactica Myosotis Alpestris," which she used against Usagi. Myosotis alpestris is the name of an alpine species of Forget-me-not.